Bloomrun is a tiny (≈2.5 KB gzipped) JavaScript library that lets you store patterns—objects whose properties may include regular expressions—and efficiently retrieve matching entries in either insertion order or depth‑first order. It’s aimed at developers who need fast, in‑browser or Node.js pattern‑based lookups (e.g., routing, rule engines) and want a simple API for adding, removing, iterating, and defaulting payloads tied to those patterns.